A bone screw is shown in EP-A-0 614 649 which must be inserted through a reception part prior to being rotated into an implant, which is a hindrance during the rotating in. Precisely in vertebral corrections a plurality of bone screws of this kind, which are screwed into different vertebrae, are connected to one another via connection rods and reception parts. The reception part is designed in the shape of a tower and receives the spherical head of the bone screw within itself. The bone screw is pivotally journalled at a counter-shell with its spherical head and can be fixed to the reception part either directly by a clamping screw or indirectly by a clamping screw via intermediate members such as connection rod and pressure disc.
Similar considerations are shown in DE-A-195 42 116 for a plate-shaped reception part which is pivotal about the common centre of these spherical surfaces prior to the fixing of spherical surfaces of the screw head.
Common to both arrangements is that the bone screw must be screwed in through the reception part.